Late Cretaceous-Early Tertiary Development of Depositional Basins in Samaria as a Reflection of Eastern Mediterranean Tectonic Evolution

Abstract

The Mt. Scopus Group in Israel consists of chalk, chert, phosphorite, organic-rich carbonate (locally known as oil shale), and shale of Coniacian- Paleocene age. The rock sequence includes several rock units, including the En-Zeitim Formation (with the related Har-Zefat Member), Mishash Formation, and Biriya Formation. Within the study area, the thicknesses of these rock units vary considerably (100-600 m), reflecting the geometry of basins that formed after the end of the Turonian and evolved during the early-late Senonian. Following the opening of the South Atlantic ridge during the Late Cretaceous, the convergence between Afro-Arabia and Eurasia generated a regional compressive regime throughout the eastern Mediterranean region. This compression formed the Syrian arc fold system that is characterized by a general northeastern direction; however, preexisting northeast- and northwest-directed fold and fault patterns responded differently in various areas. Chains of depocenters aligned along the northwest-directed faults subsided during different time increments. The bituminous chalk of Mt. Scopus Group preserved in these depocenters is considered a genuine petroleum source rock with a total organic carbon content of 10-15 wt. %. The tectonic pattern and the three-dimensional distribution of the impermeable sediments of Mt. Scopus Group are also important for groundwater exploitation in the area.